Different flywheels have different timing numbers for the ball position. Most of them position the ball at 5 degrees before TDC, but the width of the ball itself can vary that number by about +/- 1 degree. Then there are manufacturing tolerances to consider for several parts- - -the keyway in the crankshaft, the bolt holes and dowel rods in the crankshaft hub, the flywheel itself, and a few other factors, including the position of the pointer itself. The only way to be absolutely sure of the timing would be to use a degree wheel, a dial indicator, and/or a "positive stop" of the piston travel to measure the parts of a specific engine. Nobody but a race engine builder would go to those extremes, for the most part. Get the static timing in the ballpark, and then tweak the distributor position a little at a time to get the best performance for a specific engine. The engine won't care, and nobody but an obsessive-compulsive service manual reader will care, either. These engines are not running in Formula One races at 15K RPM! They were intended to be serviced out in the boondocks by Farmer John with a 4th. Grade education and crops to harvest!
Jerry
